How a photo is fitted to a KB limit
The maximum is counted as N × 1,000 bytes. A result marked 20 KB is at most 20,000 bytes, so it also fits a portal that counts 1 KB as 1,024 bytes. If you set a minimum, that floor uses ×1,024. A 10 KB minimum is 10,240 bytes. The stricter pair is deliberate: forms disagree about which kilobyte they mean, and a file that clears both is less likely to be rejected.
Quality is tried first, from sharper to smaller, at the pixel size you asked for. If the JPEG is still over the cap, the picture is scaled down by about 10% and tried again. The result shows the final width and height, because a portal that also checks pixels needs that number. Output is always a JPG. A transparent PNG is placed on white, since JPG has no transparency.
Pixels, centimetres, and a size band
Leave width and height empty when you only care about the file size. Fill them when the form prints a size. Centimetres and inches are converted with the DPI you enter: pixels = centimetres ÷ 2.54 × DPI. That DPI is also written into the JPG, which is what some upload checks read.
A minimum is optional. If the JPEG is still under the floor after quality is raised, a comment is added to the file so the byte count clears the floor. The picture does not change, and the result says the file was padded. You can resize up to 10 photos, one after another, so a low-end phone is not asked to hold them all at once.
Other sizes
- Resize image to 20KB — common photo cap, including some PAN photos
- Resize image to 50KB — a middle size for forms that reject 100KB
- Resize image to 100KB — a photo, not a PDF
- Resize image to 200KB — more detail than a 20KB export
- Signature resizer — a scanned signature in a 10–20 KB or 30–49 KB band